Biotechnology for Biofuels最新文献

{"title":"Propionate production by Bacteroidia gut bacteria and its dependence on substrate concentrations differs among species","authors":"Carolin Döring,&nbsp;Mirko Basen","doi":"10.1186/s13068-024-02539-9","DOIUrl":"10.1186/s13068-024-02539-9","url":null,"abstract":"<div><h3>Background</h3><p>Propionate is a food preservative and platform chemical, but no biological process competes with current petrochemical production routes yet. Although propionate production has been described for gut bacteria of the class <i>Bacteroidia</i>, which also carry great capacity for the degradation of plant polymers, knowledge on propionate yields and productivities across species is scarce. This study aims to compare propionate production from glucose within <i>Bacteroidia</i> and characterize good propionate producers among this group.</p><h3>Results</h3><p>We collected published information on propionate producing <i>Bacteroidia,</i> and selected ten species to be further examined. These species were grown under defined conditions to compare their product formation. While propionate, acetate, succinate, lactate and formate were produced, the product ratios varied greatly among the species. The two species with highest propionate yield, <i>B. propionicifaciens</i> (0.39 g_pro/g_gluc) and <i>B. graminisolvens</i> (0.25 g_pro/g_gluc), were further examined. Product formation and growth behavior differed significantly during CO₂-limited growth and in resting cells experiments, as only <i>B. graminisolvens</i> depended on external-added NaHCO₃, while their genome sequences only revealed few differences in the major catabolic pathways. Carbon mass and electron balances in experiments with resting cells were closed under the assumption that the oxidative pentose pathway was utilized for glucose oxidation next to glycolysis in <i>B. graminisolvens</i>. Finally, during pH-controlled fed-batch cultivation <i>B. propionicifaciens</i> and <i>B. graminisolvens</i> grew up to cell densities (OD₆₀₀) of 8.1 and 9.8, and produced 119 mM and 33 mM of propionate from 130 and 105 mM glucose, respectively. A significant production of other acids, particularly lactate (25 mM), was observed in <i>B. graminisolvens</i> only.</p><h3>Conclusions</h3><p>We obtained the first broad overview and comparison of propionate production in <i>Bacteroidia</i> strains. A closer look at two species with comparably high propionate yields, showed significant differences in their physiology. Further studies may reveal the molecular basis for high propionate yields in <i>Bacteroidia</i>, paving the road towards their biotechnological application for conversion of biomass-derived sugars to propionate.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02539-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141569819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Emerging methylation-based approaches in microbiome engineering","authors":"Changhee Won,&nbsp;Sung Sun Yim","doi":"10.1186/s13068-024-02529-x","DOIUrl":"10.1186/s13068-024-02529-x","url":null,"abstract":"<div><p>Bacterial epigenetics, particularly through DNA methylation, exerts significant influence over various biological processes such as DNA replication, uptake, and gene regulation in bacteria. In this review, we explore recent advances in characterizing bacterial epigenomes, accompanied by emerging strategies that harness bacterial epigenetics to elucidate and engineer diverse bacterial species with precision and effectiveness. Furthermore, we delve into the potential of epigenetic modifications to steer microbial functions and influence community dynamics, offering promising opportunities for understanding and modulating microbiomes. Additionally, we investigate the extensive diversity of DNA methyltransferases and emphasize their potential utility in the context of the human microbiome. In summary, this review highlights the potential of DNA methylation as a powerful toolkit for engineering microbiomes.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02529-x","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141581837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Efficient synthesis of limonene production in Yarrowia lipolytica by combinatorial engineering strategies","authors":"Young-Kyoung Park,&nbsp;Lara Sellés Vidal,&nbsp;David Bell,&nbsp;Jure Zabret,&nbsp;Mladen Soldat,&nbsp;Martin Kavšček,&nbsp;Rodrigo Ledesma-Amaro","doi":"10.1186/s13068-024-02535-z","DOIUrl":"10.1186/s13068-024-02535-z","url":null,"abstract":"<div><h3>Background</h3><p>Limonene has a variety of applications in the foods, cosmetics, pharmaceuticals, biomaterials, and biofuels industries. In order to meet the growing demand for sustainable production of limonene at industry scale, it is essential to find an alternative production system to traditional plant extraction. A promising and eco-friendly alternative is the use of microbes as cell factories for the synthesis of limonene.</p><h3>Results</h3><p>In this study, the oleaginous yeast <i>Yarrowia lipolytica</i> has been engineered to produce <span>d</span>- and <span>l</span>-limonene. Four target genes, <i><span>l</span></i>- or <i><span>d</span></i>-<i>LS</i> (limonene synthase), <i>HMG</i> (HMG-CoA reductase), <i>ERG20</i> (geranyl diphosphate synthase), and <i>NDPS1</i> (neryl diphosphate) were expressed individually or fused together to find the optimal combination for higher limonene production. The strain expressing HMGR and the fusion protein ERG20-LS was the best limonene producer and, therefore, selected for further improvement. By increasing the expression of target genes and optimizing initial OD, 29.4 mg/L of <span>l</span>-limonene and 24.8 mg/L of <span>d</span>-limonene were obtained. We also studied whether peroxisomal compartmentalization of the synthesis pathway was beneficial for limonene production. The introduction of <span>d</span>-LS and ERG20 within the peroxisome improved limonene titers over cytosolic expression. Then, the entire MVA pathway was targeted to the peroxisome to improve precursor supply, which increased <span>d</span>-limonene production to 47.8 mg/L. Finally, through the optimization of fermentation conditions, <span>d</span>-limonene production titer reached 69.3 mg/L.</p><h3>Conclusions</h3><p>In this work, <i>Y. lipolytica</i> was successfully engineered to produce limonene. Our results showed that higher production of limonene was achieved when the synthesis pathway was targeted to the peroxisome, which indicates that this organelle can favor the bioproduction of terpenes in yeasts. This study opens new avenues for the efficient synthesis of valuable monoterpenes in <i>Y. lipolytica</i>.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02535-z","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141499904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phosphate limitation enhances malic acid production on nitrogen-rich molasses with Ustilago trichophora","authors":"Luca Antonia Grebe,&nbsp;Philipp Georg Lichtenberg,&nbsp;Katharina Hürter,&nbsp;Eva Forsten,&nbsp;Katharina Miebach,&nbsp;Jochen Büchs,&nbsp;Jørgen Barsett Magnus","doi":"10.1186/s13068-024-02543-z","DOIUrl":"10.1186/s13068-024-02543-z","url":null,"abstract":"<div><h3>Background</h3><p>An important step in replacing petrochemical products with sustainable, cost-effective alternatives is the use of feedstocks other than, e.g., pure glucose in the fermentative production of platform chemicals. Ustilaginaceae offer the advantages of a wide substrate spectrum and naturally produce a versatile range of value-added compounds under nitrogen limitation. A promising candidate is the dicarboxylic acid malic acid, which may be applied as an acidulant in the food industry, a chelating agent in pharmaceuticals, or in biobased polymer production. However, fermentable residue streams from the food and agricultural industry with high nitrogen content, e.g., sugar beet molasses, are unsuited for processes with Ustilaginaceae, as they result in low product yields due to high biomass and low product formation.</p><h3>Results</h3><p>This study uncovers challenges in evaluating complex feedstock applicability for microbial production processes, highlighting the role of secondary substrate limitations, internal storage molecules, and incomplete assimilation of these substrates. A microliter-scale screening method with online monitoring of microbial respiration was developed using malic acid production with <i>Ustilago trichophora</i> on molasses as an application example. Investigation into nitrogen, phosphate, sulphate, and magnesium limitations on a defined minimal medium demonstrated successful malic acid production under nitrogen and phosphate limitation. Furthermore, a reduction of nitrogen and phosphate in the elemental composition of <i>U. trichophora</i> was revealed under the respective secondary substrate limitation. These adaptive changes in combination with the intricate metabolic response hinder mathematical prediction of product formation and make the presented screening methodology for complex feedstocks imperative. In the next step, the screening was transferred to a molasses-based complex medium. It was determined that the organism assimilated only 25% and 50% of the elemental nitrogen and phosphorus present in molasses, respectively. Due to the overall low content of bioavailable phosphorus in molasses, the replacement of the state-of-the-art nitrogen limitation was shown to increase malic acid production by 65%.</p><h3>Conclusion</h3><p>The identification of phosphate as a superior secondary substrate limitation for enhanced malic acid production opens up new opportunities for the effective utilization of molasses as a more sustainable and cost-effective substrate than, e.g., pure glucose for biobased platform chemical production.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02543-z","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141499905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Designing a highly efficient type III polyketide whole-cell catalyst with minimized byproduct formation","authors":"La Xiang,&nbsp;Xuanxuan Zhang,&nbsp;Yanyan Lei,&nbsp;Jieyuan Wu,&nbsp;Guangru Yan,&nbsp;Wei Chen,&nbsp;Shizhong Li,&nbsp;Wenzhao Wang,&nbsp;Jian-Ming Jin,&nbsp;Chaoning Liang,&nbsp;Shuang-Yan Tang","doi":"10.1186/s13068-024-02545-x","DOIUrl":"10.1186/s13068-024-02545-x","url":null,"abstract":"<div><h3>Background</h3><p>Polyketide synthases (PKSs) are classified into three types based on their enzyme structures. Among them, type III PKSs, catalyzing the iterative condensation of malonyl-coenzyme A (CoA) with a CoA-linked starter molecule, are important synthases of valuable natural products. However, low efficiency and byproducts formation often limit their applications in recombinant overproduction.</p><h3>Results</h3><p>Herein, a rapid growth selection system is designed based on the accumulation and derepression of toxic acyl-CoA starter molecule intermediate products, which could be potentially applicable to most type III polyketides biosynthesis. This approach is validated by engineering both chalcone synthases (CHS) and host cell genome, to improve naringenin productions in <i>Escherichia coli</i>. From directed evolution of key enzyme CHS, beneficial mutant with ~ threefold improvement in capability of naringenin biosynthesis was selected and characterized. From directed genome evolution, effect of thioesterases on CHS catalysis is first discovered, expanding our understanding of byproduct formation mechanism in type III PKSs. Taken together, a whole-cell catalyst producing 1082 mg L⁻¹ naringenin in flask with<i> E</i> value (evaluating product specificity) improved from 50.1% to 96.7% is obtained.</p><h3>Conclusions</h3><p>The growth selection system has greatly contributed to both enhanced activity and discovery of byproduct formation mechanism in CHS. This research provides new insights in the catalytic mechanisms of CHS and sheds light on engineering highly efficient heterologous bio-factories to produce naringenin, and potentially more high-value type III polyketides, with minimized byproducts formation.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02545-x","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141499903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhancement of protein production in Aspergillus niger by engineering the antioxidant defense metabolism","authors":"Xin Chen,&nbsp;Baoxiang Pan,&nbsp;Leyi Yu,&nbsp;Bin Wang,&nbsp;Li Pan","doi":"10.1186/s13068-024-02542-0","DOIUrl":"10.1186/s13068-024-02542-0","url":null,"abstract":"<div><h3>Background</h3><p>Research on protein production holds significant importance in the advancement of food technology, agriculture, pharmaceuticals, and bioenergy. <i>Aspergillus niger</i> stands out as an ideal microbial cell factory for the production of food-grade proteins, owing to its robust protein secretion capacity and excellent safety profile. However, the extensive oxidative folding of proteins within the endoplasmic reticulum (ER) triggers ER stress, consequently leading to protein misfolding reactions. This stressful phenomenon results in the accelerated generation of reactive oxygen species (ROS), thereby inducing oxidative stress. The accumulation of ROS can adversely affect intracellular DNA, proteins, and lipids.</p><h3>Result</h3><p>In this study, we enhanced the detoxification of ROS in <i>A. niger</i> (SH-1) by integrating multiple modules, including the NADPH regeneration engineering module, the glutaredoxin system, the GSH synthesis engineering module, and the transcription factor module. We assessed the intracellular ROS levels, growth under stress conditions, protein production levels, and intracellular GSH content. Our findings revealed that the overexpression of <i>Glr1</i> in the glutaredoxin system exhibited significant efficacy across various parameters. Specifically, it reduced the intracellular ROS levels in <i>A. niger</i> by 50%, boosted glucoamylase enzyme activity by 243%, and increased total protein secretion by 88%.</p><h3>Conclusion</h3><p>The results indicate that moderate modulation of intracellular redox conditions can enhance overall protein output. In conclusion, we present a strategy for augmenting protein production in <i>A. niger</i> and propose a potential approach for optimizing microbial protein production system.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02542-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141478190","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Revision of the sophorolipid biosynthetic pathway in Starmerella bombicola based on new insights in the substrate profile of its lactone esterase","authors":"Zhoujian Diao,&nbsp;Sophie L. K. W. Roelants,&nbsp;Goedele Luyten,&nbsp;Jan Goeman,&nbsp;Isabel Vandenberghe,&nbsp;Gonzalez Van Driessche,&nbsp;Sofie L. De Maeseneire,&nbsp;Wim K. Soetaert,&nbsp;Bart Devreese","doi":"10.1186/s13068-024-02533-1","DOIUrl":"10.1186/s13068-024-02533-1","url":null,"abstract":"<div><h3>Background</h3><p>Sophorolipids (SLs) are a class of natural, biodegradable surfactants that found their way as ingredients for environment friendly cleaning products, cosmetics and nanotechnological applications. Large-scale production relies on fermentations using the yeast <i>Starmerella bombicola</i> that naturally produces high titers of SLs from renewable resources. The resulting product is typically an extracellular mixture of acidic and lactonic congeners. Previously, we identified an esterase, termed <i>Starmerella bombicola</i> lactone esterase (SBLE), believed to act as an extracellular reverse lactonase to directly use acidic SLs as substrate.</p><h3>Results</h3><p>We here show based on newly available pure substrates, HPLC and mass spectrometric analysis, that the actual substrates of SBLE are in fact bola SLs, revealing that SBLE actually catalyzes an intramolecular transesterification reaction. Bola SLs contain a second sophorose attached to the fatty acyl group that acts as a leaving group during lactonization.</p><h3>Conclusions</h3><p>The biosynthetic function by which the <i>Starmerella bombicola</i> ‘lactone esterase’ converts acidic SLs into lactonic SLs should be revised to a ‘transesterase’ where bola SL are the true intermediate. This insights paves the way for alternative engineering strategies to develop designer surfactants.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02533-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141453558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploration of Trichoderma reesei as an alternative host for erythritol production","authors":"Audrey Masi,&nbsp;Georg Stark,&nbsp;Johanna Pfnier,&nbsp;Robert L. Mach,&nbsp;Astrid R. Mach-Aigner","doi":"10.1186/s13068-024-02537-x","DOIUrl":"10.1186/s13068-024-02537-x","url":null,"abstract":"<div><h3>Background</h3><p>Erythritol, a natural polyol, is a low-calorie sweetener synthesized by a number of microorganisms, such as <i>Moniliella pollinis</i>. Yet, a widespread use of erythritol is limited by high production costs due to the need for cultivation on glucose-rich substrates. This study explores the potential of using <i>Trichoderma reesei</i> as an alternative host for erythritol production, as this saprotrophic fungus can be cultivated on lignocellulosic biomass residues. The objective of this study was to evaluate whether such an alternative host would lead to a more sustainable and economically viable production of erythritol by identifying suitable carbon sources for erythritol biosynthesis, the main parameters influencing erythritol biosynthesis and evaluating the feasibility of scaling up the defined process.</p><h3>Results</h3><p>Our investigation revealed that <i>T. reesei</i> can synthesize erythritol from glucose but not from other carbon sources like xylose and lactose. <i>T. reesei</i> is able to consume erythritol, but it does not in the presence of glucose. Among nitrogen sources, urea and yeast extract were more effective than ammonium and nitrate. A significant impact on erythritol synthesis was observed with variations in pH and temperature. Despite successful shake flask experiments, the transition to bioreactors faced challenges, indicating a need for further scale-up optimization.</p><h3>Conclusions</h3><p>While <i>T. reesei</i> shows potential for erythritol production, reaching a maximum concentration of 1 g/L over an extended period, its productivity could be improved by optimizing the parameters that affect erythritol production. In any case, this research contributes valuable insights into the polyol metabolism of <i>T. reesei</i>, offering potential implications for future research on glycerol or mannitol production. Moreover, it suggests a potential metabolic association between erythritol production and glycolysis over the pentose phosphate pathway.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02537-x","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141453560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"De novo biosynthesis of β-arbutin in Corynebacterium glutamicum via pathway engineering and process optimization","authors":"Bin Zhang,&nbsp;Kexin Gou,&nbsp;Kexin Xu,&nbsp;Zhimin Li,&nbsp;Xiaoyan Guo,&nbsp;Xiaoyu Wu","doi":"10.1186/s13068-024-02540-2","DOIUrl":"10.1186/s13068-024-02540-2","url":null,"abstract":"<div><h3>Background</h3><p>β-Arbutin, a hydroquinone glucoside found in pears, bearberry leaves, and various plants, exhibits antioxidant, anti-inflammatory, antimicrobial, and anticancer effects. β-Arbutin has wide applications in the pharmaceutical and cosmetic industries. However, the limited availability of high-performance strains limits the biobased production of β-arbutin.</p><h3>Results</h3><p>This study established the β-arbutin biosynthetic pathway in <i>C. glutamicum</i> ATCC13032 by introducing codon-optimized <i>ubiC</i>, <i>MNX1</i>, and <i>AS</i>. Additionally, the production titer of β-arbutin was increased by further inactivation of <i>csm</i> and <i>trpE</i> to impede the competitive metabolic pathway. Further modification of the upstream metabolic pathway and supplementation of UDP-glucose resulted in the final engineered strain, <i>C. glutamicum</i> AR11, which achieved a β-arbutin production titer of 7.94 g/L in the optimized fermentation medium.</p><h3>Conclusions</h3><p>This study represents the first successful instance of de novo β-arbutin production in <i>C. glutamicum</i>, offering a chassis cell for β-arbutin biosynthesis.</p></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02540-2","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141448066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of fed-batch strategy to fully eliminate the negative effect of lignocellulose-derived inhibitors in ABE fermentation","authors":"Barbora Branska,&nbsp;Kamila Koppova,&nbsp;Marketa Husakova,&nbsp;Petra Patakova","doi":"10.1186/s13068-024-02520-6","DOIUrl":"10.1186/s13068-024-02520-6","url":null,"abstract":"<div><h3>Background</h3><p>Inhibitors that are released from lignocellulose biomass during its treatment represent one of the major bottlenecks hindering its massive utilization in the biotechnological production of chemicals. This study demonstrates that negative effect of inhibitors can be mitigated by proper feeding strategy. Both, crude undetoxified lignocellulose hydrolysate and complex medium supplemented with corresponding inhibitors were tested in acetone–butanol–ethanol (ABE) fermentation using <i>Clostridium beijerinckii</i> NRRL B-598 as the producer strain.</p><h3>Results</h3><p>First, it was found that the sensitivity of <i>C. beijerinckii</i> to inhibitors varied with different growth stages, being the most significant during the early acidogenic phase and less pronounced during late acidogenesis and early solventogenesis. Thus, a fed-batch regime with three feeding schemes was tested for toxic hydrolysate (no growth in batch mode was observed). The best results were obtained when the feeding of an otherwise toxic hydrolysate was initiated close to the metabolic switch, resulting in stable and high ABE production. Complete utilization of glucose, and up to 88% of xylose, were obtained. The most abundant inhibitors present in the alkaline wheat straw hydrolysate were ferulic and coumaric acids; both phenolic acids were efficiently detoxified by the intrinsic metabolic activity of clostridia during the early stages of cultivation as well as during the feeding period, thus preventing their accumulation. Finally, the best feeding strategy was verified using a TYA culture medium supplemented with both inhibitors, resulting in 500% increase in butanol titer over control batch cultivation in which inhibitors were added prior to inoculation.</p><h3>Conclusion</h3><p>Properly timed sequential feeding effectively prevented acid-crash and enabled utilization of otherwise toxic substrate. This study unequivocally demonstrates that an appropriate biotechnological process control strategy can fully eliminate the negative effects of lignocellulose-derived inhibitors.</p><h3>Graphical Abstract</h3>\u0000<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":494,"journal":{"name":"Biotechnology for Biofuels","volume":"17 1","pages":""},"PeriodicalIF":6.1,"publicationDate":"2024-06-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://biotechnologyforbiofuels.biomedcentral.com/counter/pdf/10.1186/s13068-024-02520-6","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141447793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}